From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@quanstro.net>
Date: Sat,  8 May 2010 00:41:42 -0400
To: 9fans@9fans.net
Message-ID: <f398739f6a0b9662b674629ff984fb5c@kw.quanstro.net>
In-Reply-To: <4be4dd37.NDxcevbsQ+CfYFvN%yard-ape@telus.net>
References: <l2z13426df11005061336rd8777354lf0df88db701de203@mail.gmail.com>
	<c4a516ce5a5526eb8da73bb057a3b69b@9netics.com>
	<n2n13426df11005061445y5d0c9827rf5109b02e1f50941@mail.gmail.com>
	<s2xa4e6962a1005070609icbdfdf17r6f692d40d756d5a0@mail.gmail.com>
	<4be4dd37.NDxcevbsQ+CfYFvN%yard-ape@telus.net>
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Subject: Re: [9fans] Binary File split
Topicbox-Message-UUID: 1e3680ba-ead6-11e9-9d60-3106f5b1d025

On Fri May  7 23:42:15 EDT 2010, yard-ape@telus.net wrote:
> How might I split a file into pieces specified by size?
>
> split(1) lets me specify lines and regex contexts as delimiters, but what if I want a 40MB file split up into 1.44MB chunks, say?

in retrospect, this would be better in c.  sometimes
it's just a challenge to use a screwdriver like a pry bar.

- erik

---

#!/bin/rc
if(~ $#* 0 1){
	echo usage: bsplit sz file >[1=2]
	exit usage
}
ch=$1
shift
for(i){
	sz=`{ls -ld $i | awk '{print $6}'}
	j = `{awk 'BEGIN{
		sz = ENVIRON["sz"]
		ch = ENVIRON["ch"]

		digits = log((sz + ch - 1)/ch)/log(16);
		o = 0;
		for(i = 0;; i++){
			if(o + ch >= sz)
				break;
			print i
			printf "%.*x\n", digits, i
			o += ch
		}
		if(o < sz){
			print i
			printf "%.*x\n", digits, i
		}

		}'
	}
	while(! ~ $#j 0){
		dd -if $i -of $i^$j(2) -iseek $j(1) -count 1 -bs $ch >[2=]
		j = $j(3-)
	}
}